This invention relates to novel polymer compositions having immobilized bacterial cells and/or immobilized enzyme, in which the enzyme or cells are dispersed within the polymer and to a process for producing the same.
An enzyme industry is one which produces medicine and food by carrying out enzyme reactions in the presence of enzyme or bacterial cells. Recently enzyme industries have become important and have made remarkable progress.
In the prior art, after the enzyme was dissolved in water, the enzyme reaction was effected by using the enzyme or cells solution. In this case, however, after the reaction is completed, the enzyme solution employed in the reaction cannot be reused, because the used enzyme solution contains the resulting reaction product. Therefore, the batch system must be used for the enzyme reaction. In other words, in an enzyme reaction using enzyme solution, maximum effectiveness of the enzyme is not obtained.
In recent years, attempts have been made to prepare an enzyme-polymer composition which could be reused in the enzyme reaction many times. One such composition comprises dispersing the enzyme into a polymeric material or bonding the enzyme to the polymer, and then forming a porous gel or particles from the resulting dispersion. In other words, the research has been directed toward immobilizing an enzyme or making the enzyme insoluble.
For example, one process for immobilizing an enzyme comprises dissolving a water-soluble monomer, such as acrylamide, in an aqueous solution of enzyme, and then simultaneously polymerizing and crosslinking the monomer to form a gel comprising the resulting polymer and the enzyme, and evaporating water from the gel to form a porous material.
Another process for immobilizing an enzyme comprises dissolving a water-soluble polyvinyl alcohol in an enzyme solution and then effecting crosslinking thereof by a known process and evaporating water from the solution to form a porous material. In these processes, the enzyme is dispersed in a water-soluble polymer, whereby the enzyme is immobilized or is made insoluble to some extent.
However, the prior processes have the following disadvantages. In these processes, since the monomer to be polymerized as well as the polymer thus formed are water soluble, the polymer composition obtained by the polymerization is a clear gel in which the enzyme and the polymer are dissolved in water. In order to obtain the porous material necessary for carrying out the enzyme reaction from the gel, the large amount of water contained in the gel must be removed. In addition, the porous material obtained by removing water has large lumps comprising a firm, rigid and porous gel. A satisfactory enzyme reaction cannot be effected by using a lumpy gel, because the total surface area of the large lumps is small. Therefore, in order to carry out the enzyme reaction effectively, the large lumps of gel must be ground or pulverized to increase the surface area of the porous material. However, the removal of water from the gel and grinding the large lumps of gel require much time and much labor. In addition, since the polyacrylamide is noxious, a porous material containing the polyacrylamide and the enzyme is not usable in the food industry.
The present invention eliminates these disadvantages. The present invention provides a porous material obtained by polymerizing a specific monomer containing an enzyme or bacterial cells.